You heavy tank rat bastards! My JgIV TD is more or less useless when I see you guys roll up. The 88m with regular anti-armor rounds just bounds off.

When the AP rounds aren't penetrating or doing damage, switch to HE and learn to find the weak spots on the heavy tanks. You can also get the Hitzone Skin pack which is useful at close to mid-range but not useful when sniping at long range or if your gun is not that accurate.